在中间件中设置要在模板中访问的变量 [英] Setting a variable in middleware to be accessed in the template

问题描述

我似乎很难在我可以在模板层中访问的一个中间件类中设置变量。

I seem to be having difficulty setting a variable in one of my middleware classes that I can then access in the template layer.

基本布局是这样的：

class TheMiddleware(object):
    def __init__(self, etc):
        stuff...

    def process_response(self, request, response):
        request.my_var = "whatever"
        return response

然后在模板上查看其他视图：

Then on the template for a different view I have:

{% custom_tag arg_a %}

这是一个模板标签，应从请求中返回变量：

Which is is a template tag that should return the variable from the request:

@register.simple_tag
def custom_tag(arg_a):
    return threading.currentThread().request.my_var

此错误以呈现时捕获的AttributeError出现：'WSGIRequest'对象没有属性' my_var'

我认为这可能是我在模版标签中访问请求的方式。因此，我在此问题中添加了django.core.context_processors.request到我的TEMPLATE_CONTEXT_PROCESSORS中。 / a>并尝试将请求对象传递给标记，然后直接从模板访问请求，但是没有运气。

I thought it might be the way I was accessing the request in the template tag. So I added django.core.context_processors.request to my TEMPLATE_CONTEXT_PROCESSORS as in This question and tried passing the request object to the tag, then accessing request directly from the template but with no luck.

我想我对请求对象的方式缺乏了解工作。是否可以将变量分配给请求对象并在多个视图上选取该变量？我以为请求对象是通过视图传递的，但似乎却生成了一个新实例。

I think I lack an understanding on how request objects work. Is it possible to assign a variable to a request object and pick that variable up several views on? I thought the request object was passed through the views, but it seems that instead a new instance is generated.

如果是这种情况，您将如何在中间件中存储全局变量，然后可以从应用程序的任何位置访问它，无论是在视图中还是在视图中模板？

If that is the case, how would you go about storing a global variable within middleware that you could then access from any point in your app, be it in a view or a template?

更新：

要消除混乱（是否属于我或其他不确定的事物！）我不试图在视图的process_response中间件中设置请求变量，然后在同一视图的模板中将其提取。据我了解，这是行不通的，因为在保存变量之前已对模板进行了处理。 （这是我的故意行为。）

To clear up the confusion (whether mine or others I'm not sure!) I'm not trying to set the request variable in the process_response middleware of a view and then pick it up in the template of that same view. I understand that that wouldn't work because the template has been processed before the variable is saved. (This is a deliberate act on my part).

我有两个视图，分别是 view1 和 view2 有一个装饰器，该装饰器使中间件在请求中设置变量。希望在设置变量之后使用view2模板。

I have two views, view1 and view2 view one has a decorator that causes the middleware to set the variable in the request. It is the view2 template, which comes after the variable has been set, that I wish to access the variable.

推荐答案

您尝试

我认为您应该实现 process_request（）而不是设置变量。

I think you should be implementing process_request() instead to set the variable.

def process_request(self, request):
    request.my_var = "whatever"
    return 

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